Distinguishing between preganglionic and postganglionic injuries preoperatively can be difficult following brachial plexus injury. The purpose of this study was to assess, at individual nerve root levels, the accuracy of pre-operative diagnosis following evaluation by physical examination, imaging (CT, MRI) electromyography(EMG).

Methods:

Consecutive patients with non-penetrating traumatic brachial plexus injury requiring surgery by the same surgical team between2005 to 2016 were included in the study. Pre-operative assessments of nerve root injury were made at individual nerve root levels using physical examination, MRI, CT myelogram, and electrophysiologic studies (EMG). The results were compared to intraoperative findings. Patient demographics were also recorded.

Results:

Sixty patients were included in the study. Nine patients were female, 51 patients were male. Fifty four patients had CT myelogram, MRI or both. Fifty-five patients had EMG. All patients had a physical examination. Median patient age was 38 years and median BMI was 27.6. Considering all the nerve roots studied, the accuracy of CT myelogram /MRI was 77.8%, physical examination was 76.7% and EMG was 73.1%, however, physical examination was the most accurate for injury diagnosis of the upper roots while CT myelogram/MRI was the most accurate for the lower roots. The greatest accuracy of each of the tests was for injury diagnosis at the T1: CT/MRI 88.9%, physical examination 81.7% and EMG 76.4%. CT/MRI and EMG were least accurate at C5 (64.8% and 69.1) while physical examination was least accurate a C7 (60.7%). When considering combinations of tests, the greatest accuracy was again seen at T1.Injury status of T1 was also the most accurately diagnosed among patients with a BMI > 30. CT myelogram/MRI and physical examination were equally the most accurate in the pre-operative diagnosis in the >30 BMI subgroup.

Discussion and conclusion:

Based on the results of this study, physical examination is the most accurate for injury diagnosis of the upper nerve roots in brachial plexus injury while CT myelogram/MRI is the most accurate for the lower roots (C7, C8 and T1). The injury status of T1 is more accurately assess pre-operatively irrespective of the test performed. We conclude that advanced imaging and EMG does not necessarily add diagnostic acumen over physical examination in upper nerve root brachial plexus injury but does improve the pre-operative diagnostic ability of the lower nerve roots.